/*
 * Copyright � 2002-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

using System.Collections;
using Spring.Core.TypeConversion;

namespace Spring.Expressions.Processors;

/// <summary>
/// Converts all elements in the input list to a given target type.
/// </summary>
/// <author>Erich Eichinger</author>
public class ConversionProcessor : ICollectionProcessor
{
    /// <summary>
    /// Processes a list of source items and returns a result.
    /// </summary>
    /// <param name="source">
    /// The source list to process.
    /// </param>
    /// <param name="args">
    /// An optional processor arguments array.
    /// </param>
    /// <returns>
    /// The processing result.
    /// </returns>
    public object Process(ICollection source, object[] args)
    {
        if (source == null
            || source.Count == 0)
        {
            return source;
        }

        Type targetType = typeof(double);
        if (args == null || args.Length == 0)
        {
            throw new ArgumentNullException("args", "convert() processor requires a Type value argument.");
        }
        else if (args.Length == 1)
        {
            if (args[0] is Type)
            {
                targetType = (Type) args[0];
            }
            else
            {
                throw new ArgumentException("convert() processor argument must be a Type value.");
            }
        }
        else if (args.Length > 1)
        {
            throw new ArgumentException("Only a single argument can be specified for a convert() processor.");
        }

        ArrayList result = new ArrayList();
        foreach (object val in source)
        {
            object newVal = TypeConversionUtils.ConvertValueIfNecessary(targetType, val, null);
            result.Add(newVal);
        }

        return result.ToArray(targetType);
    }
}
